Radio system



' D. G. M CAA RADIO SYSTEM June 22 192s. 1,589,979

Filed June 25. 1924 2 Sheets-Sheet 1 ATTORNEY;

June 22, 1926. 1,589,979

I D. G. M cAA RADIO SYSTEM Filed June 25, 1924 2 Sheets-Sheet 2 uvvewngn.

i Arron/ver- TEE OFFICE.

DAVID G. llIoCAA, OF LANCASTER, PENNSYLVANIA, ASSIGNOB TO THE ELECTRIC AP" PARATUS (30., 0F EARKESBURG', PENNSYLVANIA, CORPORATION 0T6 PENNSYL- VANIA.

' RADIO SYSTEM.

Application filed June 25, 1924. Serial No. 722,246.

My invention relates to the reception oi high or radio frequency energy, without in tci .crence or disturbance due to other high or radio frequency energy produced art-ilicially or by natural electricity, as static, atn'iospheric's, etc, in systems i-n-Which the energy is transmitted either through the natural media or over a conductor or conductors extending between transmitting and receiving stations, for purposes of etfecting at receiving stations controls, or signals which may be either telegraphic or telephonic.

In accordance with my invention, the trequcncy of the energy which it is desired should be excluded or reduced in effect and reprcsentedby oscillations set up by static or other natural electricity is caused to be lower than the Frequency ol the energy which it is desired shall be received, and a signail-translating circuit. normally absorbsubstantiallyno energy of either the desired or undesired oscillations, is caused to absorb energy of the desired oscillations and translate it into a control or signal in response to a change in the natural period of the path or circuit which absorbs the energy from the natural media.

Further in accordance With my invention, whatever be the relation of the frequencies of the desired and undesired oscillations, the signal-translating circuit is oppositely influenced through a plurality of inductive couplings with a circuit or path in Which both. the desired and undesired oscillations are present.

llurther in accordance with my invention, the natural period of the circuit or path which absorbs the energy from the natural media includes inductances in parallel With each other and prelie ably oi ditierent mag ides, the inductance of lesser magnitude. preferably utilized for coupling to the rial-translating instrument and the larger inductance subjected to amplified received oscillations of signal or desired frequency to materially reduce the inductance of the parallel inductances and thereby change the natural frequency of the absorbing path or circuit to approach or equal the frequency of the desired oscillations or signal, an 1 thereby causing the signal-translating instrument to absorb oscillations of desired frequency.

Further inaccordance With my invention, there is'utilized for amplifying oscillations of the desired frequency a thermionic ainplifying tube hose input circuit, resonant to the frequency of the "desired oscillations and in which the tuning inductance preferably greatly predominates over the tuning capacity. is coupled, either magnetically or capacitatively, to the absorbing circuit-or path, and the coupling is preferably loose, and in any event controllable as to magnitude or degree, whereby the input circuit becomes highly selective and excludes oscillations of undesired frequency, which may reach the input circuit through said coupling, and the input circuit also sharply rejects oscillations of undesired frequency Which may be impressed thereon through the grid to plate capacity of the tube; and the aforesaid capacitative or magnetic coupling opposes, regards the input circuit, such coupling as may obtain between the input and output circuits of the tube through the capacity between the grid and anode thereof.

Further in accordance With my invention, there may be utilized with a capacitative coupling of the character above referred to means, such as a circuit tuned to the frequency of the undesired oscillations and a co-operating second capacitative coupling, toreffecting a point of zero potential as regards the oscillations of the undesired frequency, and the first named capacit-ative coupling effects coupling with the absorbing path or circuit through such point of zero potential, whereby the input circuit of the tube is further shielded i'romthe. influence ott' oscillations of undesired 'ttrequency.

Further in accordance ith my invention, there may be utilized in the capacitative coupling path between the absorbing circuit or path and the input circuit o'f the tube capacityand inductance in parallel and tuned to the frequency ot the undesired oscillat tion the inductance preferably greatly predoininatine over the capacity in such tuned or 'iarallel resonant circuit; further in accordance with my invention, th output circuit of the amplify? g tube may be reversely magnetically coupled to its input circuit to neutralize the coupling between input and output circuits atliected the grid to anode capacity of the tube; and by preference, both the rerer e magnetic coupling and the paral el resonant circuit are simultaneously employed.

My invention resides in further features and the method and appa 'atus of the character hereinafter described.

For an understanding of my method, and -for an illustration of some of the Various forms my apparatus may take, reference is to be had to the accompanying drawings, in which:

l is a diagrammatic View of radio receiving apparatus embodying my invention.

Fig. l is a diagrammatic View of apparz tus similar to that shown in Fig. 1, but utilizing a magnetic coupling in lieu of a capacitative coupling to the input circuit of the amplifier tube Fig. is a diagramn'iatic View of radio 1. ceivin apparatus in general similar to that of Fig. 1, but utilizing-3' in ascociation with the coupling to the input c a1nircuit of the plitying tube n'ieans tor istablishinu' a non: of substantially zero potential with 1 to the oscillat' i iesired Fin: 2 is a i of a modifi ation of the arr i 3 is a (llll, fll"1ll7lbl yiew of apparatus in general Sl1l.lf:l to that shoi n L but tilizi 1p in the ca 1- .lfCUlt of the amplityii Jltl capacity in parallel and onant to the frequency of the undesir .d oscillations, and utilizing also a reverse magnetic coupling .between the input and out circuits of the tube.

.niatic new ot a modifii paeitative (0trec iving stations as utilized em extendingbetween transmiif;

high frequency or carrier Way. (011( systems For brevity. however, my invention will he described in connection with ridio receiving systems utilized for any purposes such as control of moveme its of ships 0 aircatt, of picture or motion pic ture apparatus. or signaling apparatus in general, 'ncluiilina' telegraphic and telephonic signals it being understood that the t'anslating instrun'ient T hereinafter rerred to, re )resents generically any transiting; instrument, as a, telephone or a con trol instrument of any character.

earth or coenter-capacity 15 are llltlz'ltltltl the Variable tuning condenser C, which may be omitted it suitable or desirable, and the primaries P, F. The secondary S is oppositely iii-:hictirely affected by the primaries l and P whereby the circuit of the secondary not to any substantial degree aliected l oscillations of any frequency simulneously traversing; the primaries P a 1d when the sv 'itch a, in shunt to the primary 1", is in open position indicated.

c The secondary u is connected in the .uiput or grid on uit of a thermionic tube V, which utilized either as the first stage of a seiles of 'adio frequency amplifiers. or indicated, as a detector. The tube V comprises the anode a, grid 5/ and cathode or filament 7. In series with the secondary S is the variable inductance or variometer L, both shuntcc hy the tuninp condenser C.

*l auc between a terminal of the latter and the grid g is included the usual grid condenser K shunted by the id leak resistance 1. flu the anode circuit is the source of current l3 and the signal-translating instrun'ient 'l, which. ma he a 'elephone or any other control iustr or which may he the primary of the first oi one or more str es of a: do f eoguenc nnplitication. i

primary P is the inducwhich in coupled the induc "ed with the source of current i1 uit ot the thermionic anihose grid or input circuit luctance L and variable meter L, both shunted euser From a suit- C ption circuit or path, he zntenna path A to E. and t i in l,

1s piesenu pieieiably user b ielou' sail condenser, there is a ceuplinp; connection through the i" ab e condenser C to a contact mow the inductance L for varying coupling between the input or and circui of the tube V and the path /1,, t 1. 1 Hg V 1 noel a ien n a, ii to the cartn and liinii, the prefer: greatly predominates over the condenser C in the input circuit, renders such input cir- (nut highly and it 18 made selectire to the frequcn'cy of the desired oscillations, such as those representing the desired signal or control.

With theswitch s in closed position, thereby in effect cutting out the inductances P and L the antenna path is tuned, as by adjusting the condenser C, to the frequency of the desired oscillations rcpresei'iting the desired signal or control. And the circuit of the secondary S is similarly tuned by varying; the inductance L or condenser (3 or both, the inductance of the secondary ti and of the instrument L preferably greatly predominating over the capacity C the switch .9 is then opened, bringing into the antenna path the inductance L in shunt to the primary P the v1nagnitude of theinductance L being preferably materially greater than, as twice or n1ore,:the magnitude of the inductance of the primary 13 Under these circumstances, "due to the increased inductance in-the antenna path, it isdetuned with respect to the frequency of :the desired oscillations or signal, and the frequency or predominant frequency of the oscillations set up 111 the antenna path by static, atmospheric or other electrical effects is lower than the frequency of the desired oscillations, andthe decrement of the static or undesired oscillations is decreased because of the addition of inductance, and in conse quence, oscillations of undesired frequency are more readily excluded from the circuit tuned to the frequency of the desiredoscillations.

lVith the switch siopen as aforesaid, both static and signal oscillations have substantially no effect upon the circuit of the secondary S' because of its reverse couplings to the'primaries P and P and there would be no effectupont-heinstrument T exceptfor utilization of auxiliary means about to be described.

With the input circuit of the amplifying tube V tuned to the frequency of the desired oscillations, oscillations of the desired signal or control are impressed upon such input circuit through the path C L, E loosely coupled to the input circuit, the caoacity of the condenser C beino' adusted t; J

to suitable magnitude for this purpose. In general, the magnitude of the capacity C is made as small as suitable for operative purposes, whenthe oscillations due to static are of a freipiencylower than the frequency of the desiredoscillations, and under such circumstances the condenser C effects a closer coupling for oscillations of desired frequency than for scillations due to static or undesired frequency, the condenser {i in a broadisenseselectively passing oscillations of desired frequency, and the loose coupling with the input circuit of the tube V- further assists in isharply excluding oscillations of undesired {ifrequency from the input circuit.

opacity K from the inductance L Accordingly, the tube "V is affected substantially exclusively by oscillations of desired frequency, and these are amplified, in any suitable additional stages if desired, and the amplified oscillations traversing the inductance L inductively influence the inductance L to which L is preferably closely coupled, in such sense that the ind ctance vof L is in effect largely or nu 'ally reduced, whereby the inductance of Li" allel with each other is reduced, and therefore the natural period of the antenna path rrE is changed in a use approaching or equalling the vperiod of the desired oscillations. Under these circumstances, the cur rent in the primary P is found to be small or substantially nil, and tl'ierefore the secondary S is influenced only by the primary l? and only by oscillations desired frequen y, with the result that the signal-translating circuit now absorbs oscillations of desired frequency and translates them-bymeans of the instrument T. The coil P is prefer-- ably rotatable relative to the secondary S for balancing the effect upon the secondary S of the primary P Then the amplified oscillations are traversing the inductance L it is found that the primary P may be rotated practically to any position with respect to the secondary S without producing any effect thereon, and this shows the substantial or complete absence of current in the primary P when the inductance L is traversed by amplified oscillations of the desired frequency.

Such portion of the static oscillations in the antenna path which traverses the inductance-L produces a slight or partial beat effect with the oscillations of signal frequency impressed upon inductance L by inductance L nit this causes .a slight net effect by static oscillations upon the sec ondary S but this effect is of negligible magnitude. The oscillations of static frequency occurring in the inductance L may influence the input circuit of the tube V by the inductive influence of L upon the output circuit of the tube V and through the ca )acity between the arid and anode the tube V this ca 'iacity being represented in dotted lines at K The coupling effected. between. the output and input circuits by the capacity K is neutralized by the curry,- ling effected through the condenser whereby any oscillations of static frequency influencing the input circuit of the tube V through the condenser C may be caused to neutralize the effect of static oscillations reaching the input circuit throng-lithe ca- This neutralization or balancing of couplings as regards the oscillations of static frequency may be determined with great nicety by suitable -.adiustinent of the capacity of the condenser "G rand this neutralization of and P in par til Lea ers ly small compared with the sum oi? the inducta'nces L and l whereby tile larger part of: the current of the oscillations of desired and undesired frequencies in the antenna path pass through inductance L and the small current traversing the primary P counteracted in its effect upon the secondary S by the relatively small primary P whereby the circuit of the secondary S is again practically free of energy of the oscillations oi both desired and undesired frequencies. But by the action of the an'iplilier tube V and the co'u ilin-g' of its input circuit to the antenna path through the condenser C the action is in general similar to that hereinbetore described, and the signal-translat ing circuit; including the secondary S absorbs energy of the oscillations of desired frequency to the exclusion of those of undesired frequency. l' i hen amplified oscillations of desired frequency traverse the inductance IF, the indiict-ance L is in effect reduced, causing greater amount of cur rent to flow through the primary P and therefore dis'turb'the balance and cause the signal-translating instrument to absorb energy of desired frequency.

Some of the features hereinbe'tore described and claimed are claimed'in my prior Patent No. 1,521,777,,January 6, 1925.

For the sake of brevity in the appended claims, the term fsignal is employed ge'- nerically to include signals'ot any character, including telegraphic and telephonic sis" nals, and any other analogous effect, including controls; and the term static is ene ally employed to include static and; other natural electrical-onsets"and also other et iects having artificial origin such as are caused or represented by waves or oscilla tlons other than those representing the desired signal or control.

What I claim is:

1. In the reception of radio signals, the method which comprises receiving the sig nal'energy' in a path having a natural period longer than the period of the receii' ed oscillations, and changing the natural period oi? said path by the effect upon the reactance thereof of oscillations produced by local energy.

Inthe reception of radio signals, the method which comprises receiving the signal energy in a path having a natural period longer than the period of the received oscillations, and decreasing the natural period of said path by the effect upon thereactance thereof oi oscillations produced by local energy.

In the reception ot'radio signals, the method which comprises receiving the signal energy ina' path'having a'natural period longer'than'the period of thereceived oscillations, amplifying the signal oscillations, and'util-izing the amplified oscillations for ing the natural period of said path to a magnitude substantially equal to the period of the signal oscillations.

5. lhe method of reducing the effect of static in the reception of signals, which comprises receiving the signal oscillations in" a path having a natural period longer thanthe period of tho signal oscillations, subjecting a second path tuned to the static ocillations in reverse senses to the static oscillations in said firstnained path for producing in said second path a point of substantially Zero potential with respect to static oscillations, and transferring signal oscillations from said first names path to a third path tuned to the signal oscillations through said point of substantially zero potential.

(i. The method oi": reducing the etlectof static in the receptionot signals, which coinprisesreceiving the signal oscillations in a path having a natural period longer than the period of the signal oscillations,subjecting a second path tuned to the static oscillations in'rererse senses to the static oscillations in saidfirst named path for producing in said second path a point of substantially Zero p'o tential with respect to static oscillations, transferring signal oscillations fr m said first named path to athird )ath tuned to the signal'oscillations through saidp'oint or substantially Zero potentiahan'd u'tilizii'ig local energy in the form of oscillations for chang ing the natural period of said first named path.

The methodo'l reducing the (9360f of static in the reception of signals, which comprises receiving the signal oscillations in a path having anat-n'ral period longer thanthe period oi? the signal oscillations, subjectinga second path tuned to the static oscillations in reverse senses to the static oscillations in said first named path-tor producing'in saic second path a pointer substantially Zero potential with respect to static oscillations,'transfer-ring signal oscillations from said first named path to athird path tuned to the signal'oscillations through said point of sub-- stantially zero potential, amplifying signal oscillations, and utilizing the amplified oscillations for changing the natural period of said first named path.

8. In the'reception' of radio signals, the method which comprises receiving the'signal energy in a path having a natnral'period longer than the period of the" signal oscillations, influencing asignal-translating circuit in opposite senses by the static and signal oscillations in said detuned path, whereby the effect upon said sigmil-translating circuit is substantially nil, and increasing the absorption of signal energy from said path by the signal-translating circuit by influencing said path by oscillations produced by local energy to substantially tune said path to the frequency of the signal oscillations.

9. In the reception of radio signals, the method which comprises receiving the signal energy in a path detuned to the signal oscillations, subjecting a signal-translating path tuned to the signal oscillations in opposite senses to magnetic influences of oscillations in said detuned path, and modifying one of said magnetic influences by oscillations of signal frequency.

10. In the reception of radio signals, the method which comprises receiving the signal energy in a path detuned to the signal oscillations, subjecting a signal-translating path in opposite senses to magnetic influences of oscillations in said detuned path, amplifying received signal oscillations, and modifying one of said magnetic influences by the amplified oscillations.

11. A receiving system comprising a path traversed by signal and static oscillations and having a natural period which is longer than the period of the signal oscillations, and means for changing the natural period of said path comprising means for changing the reactance of said path by local oscillations.

12. A receiving system comprising a path traversed by signal and static oscillations and having a natural period which is longer than the period of the signal oscillations, and means for decreasing the natural period of said path comprising means for changing the reactance of said path by local oscillations.

13. A receiving system comprising a path traversed by signal and static oscillations and having a natural period which is longer than the period of the signal oscillations, means for amplifying oscillations of signal frequency, and means through which the amplified oscillations change the reactance of said path to change its natural period in a sense approaching the period of the signalrepresenting oscillations.

14:. A receiving system comprising a path traversed by signal and static oscillations and having a natural period which is longer than the period of the signal oscillations, means for amplifying oscillations of signal frequency, and means through which the amplified oscillations change the react-ance and thereby decrease the natural period of said path.

15. A receiving system comprising a path including inductances in parallel with each other and having a natural period longer than the period of the signal oscillations.

means for amplifying oscillations of signal frequency, and means for influencing one 0 said inductances by the amplilied oscillations; for changing the natural period of said path.

18. A receiving system comprising a path including inductances in parallel with each other and having a natural period longer than the period of the signal oscillations, means for amplifying oscillations of signal frequency, and means for influencing one of said inductances by the amplified oscillations for decreasing the natural period of said path.

19. A receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, a circuit tuned to the static oscillations. means for coupling said circuit in reverse senses to said path for establishing a point of substantially zero potential with respect to the static oscillations, a second circuit tuned to the signal oscillations. and means for transferring nal oscillations to said second circuit through said pointof zero potential.

20. A receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, a circuit tuned to the static oscillations. means for coupling said circuit in reverse senses to i path for establishing a point of subs zero potential with respect to the sta ic oscil lations, a second circuit tuned to the signal oscil ations, means for transferring signal oscillations to said second circuit through said point of zero potential, means for anplifying the signal oscillations in said second circuit, and means for decreasing the natural period of said path by the amplified oscillations.

21. A receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, a circuit tuned to the static oscillations, means for coupling said circuit in reverse senses to said path for establishing a point of substantially zero potential with respect to the static oscil lations, a second circuit tuned to the signal oscillations, means for transferring signal oscillations to said second circuit through said point of Zero potential, means for an plifying the signal oscillations in said second circuit, means for decreasing the natural period of said path by the amplified oscillations, a signal-translating circuit, and conplings between said circuit and said path for affecting said signal circuit in opposite senses to substantially equal extents.

22. A receiving system comprising a path traversed by signal and static oscillations and detuned with respect to the signal oscillations, a signa1translating circuit, couplings between said signal-translating circuit and said path for affecting said signal-translating circuit. in equal and opposite senses, a thermionic amplifier having input and output circuits, means for impressing signal oscillations upon said input circuit, means for cou pling said output circuit to said path for changing the natural period of said path by the amplified oscillations, and a coupling between said output and input circuits for neutralizing the effect upon said input circuit of static oscillations in said output circuit.

23. A receiving system comprising a path detuned to the signal oscillations and traversed by signal and static oscillations, transformer primaries in said path, a signaltranslating circuit coupled in opposite senses to said primaries, an inductance in shunt to one of said primaries, and means for influencing said inductance by local oscillations for changing the natural period of said path.

24-. A receiving system comprising a path detuned to the signal oscillations and traversed by signal and static oscillations, transformer primaries in said path, a signaltranslating circuit coupled in opposite senses to said primaries, an inductance in shunt to one of said primaries, a thermionic ampli tier having input and output circuits, means for iinpr s oscillations upon said input circun, and means for coupling said output circuit to said inductance for influencing said inductance by amplified oscillations in such sense as to reduce the effect 01": said inductance upon the natural period of said path.

25. A receiving system comprising a path dctuned to the signal oscillations and traversed by signal and static oscillations, transformer primaries in said path, a signaltranslating circuit coupled in opposite senses to said primaries, an inductance in shunt to one of said primaries, a thermionic amplifier having input and output circuits, means for coupling said input circuit to said path, AGHHS for reducing static oscillations in said coupling, and means for couplin the output circuit to said inductance for varying by the amplified oscillations the effect of said inductance upon the natural period of said path.

26. 1; receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, a signaltranslating circuit, couplings between said signal-translating circuit and said path for ah'ecting said signal-translating circuit in equal and opposite senses, a thermionic amplifier having input and output circuits, means for impressing signal oscillations upon said input circuit, means for coupling said output circuit to said path for decr-asing the natural period of said path by the amplified oscillations, and a coupling between said output and input circuits for neutralizing the eiiect upon said input circuit of static oscillations in said output circuit.

27. A receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, transformer p *imaries in said path, a signal-translating circuit coupled in opposite senses to said primaries, an inductance in shunt to one of. said primaries, and means for influencing said inductance by local oscillations for decreasing the natural period of said path.

28. A receivin system comprising a path traversed by signal and static oscillations and having a natural period longer than the period of the signal oscillations, transformer primaries in said path, a signal-translating circuit coupled in opposite senses to said IOU primaries, an inductance in shunt to one of said primaries, a thermionic amplifier having input and output circuits, means for impressing signal oscillations upon said inputcircuit, and means for coupling said output circuit to said inductance for influencing said inductance by amplified oscillations in such sense as to reduce the effect of said inductance upon the natural period of said path.

29. A receiving system comprising a path traversed by signal and static oscillations and having a natural period longer than the period oi the signal oscillations, transformer primaries in said path, signal-translating circuit coupled in opposite senses to said primaries, an inductance in shunt to one of said primaries. a thermionic amplifier having input and output circuits, means for coupling said input circuit to said path, means {or reducing static oscillations in said coupling, and means for coupling the output circuit to said inductance for varying by the amplified oscillations the effect of said inductance upon the natural period of said path.

30. A receiving system comprising a path detuned with respect to the signal oscillations and traversed by signal and static 0scillations u signal-translating circuit, means for coupling said circuit in opposite senses to said path, an inductance in said path, a thermionic amplifier having input and out put circuits said output circuit coupled to said inductance, a con; ling connection between said path

said

cir-

cuit, a coupling condenser in said connection, and an inductance and capacity in parallel with each other and in series in said coupling connection, said last nzuned inductance and capacity forming a circuit tuned to the frequency of the siucic oscillaliions.

DAVID G. lvicCikA. 

